Document options policy.

Reviewed by:	bde

sys/conf/options

@@ -1,7 +1,34 @@
-#	$Id: options,v 1.64 1998/03/04 10:24:08 dufault Exp $
-
-# Format:
+#	$Id: options,v 1.65 1998/03/08 09:56:21 julian Exp $
+#
+#        On the handling of kernel options   
+# 
+# All kernel options should be listed in LINT, with suitable
+# descriptions.  Negative options (options that make some code not
+# compile) should be commented out; LINT should compile as much code
+# as possible.  Try to structure option-using code so that a single
+# option only switch code on, or only switch code off, to make it
+# possible to have a full compile-test.  If necessary, you can include
+# "opt_lint.h" and check for COMPILING_LINT to get maximum code
+# coverage.
+# 
+# All new options shall also be listed in either "conf/options" or
+# "<machine>/conf/options.<machine>".  Options that affect a single
+# source-file <xxx>.[c|s] should be directed into "opt_<xxx>.h", while
+# options that affect multiple files should either go in
+# "opt_global.h" if this is a kernel-wide option (used just about
+# everywhere), or in "opt_<option-name-in-lower-case>.h" if it affect
+# only some files.  Note that the effect of listing only an option
+# without a header-file-name in conf/options (and cousins) is that the
+# last convention is followed.
+# 
+# This handling scheme is not yet fully implemented.
+#
+#
+# Format of this file:
 # Option name	filename
+#
+# If filename is missing, the default is
+# opt_<name-of-option-in-lower-case>.h
 
 # Miscellaneous options.
 BOUNCE_BUFFERS	opt_bounce.h